a: \(x=\dfrac{5}{14}:\dfrac{6}{7}=\dfrac{5}{14}\cdot\dfrac{7}{6}=\dfrac{5}{12}\)
b: \(x=\dfrac{4}{9}\cdot\dfrac{2}{3}=\dfrac{8}{27}\)
c: \(\dfrac{6}{x}=\dfrac{3}{4}:\left(\dfrac{3}{8}\cdot\dfrac{5}{4}\right)=\dfrac{3}{4}:\dfrac{15}{32}=\dfrac{3}{4}\cdot\dfrac{32}{15}=\dfrac{8}{5}\)
nên x=30/8=15/4
d: \(\Leftrightarrow x\cdot\dfrac{1}{3}=\dfrac{24}{315}\cdot\dfrac{7}{4}=\dfrac{2}{15}\)
nên x=2/5